Shoulder1: You are about to publish a number of studies on the rotator cuff. Could you explain to our readers what the rotator cuff is and what it does?
The rotator cuff is a group of muscles in the shoulder that aid in the elevation and rotation of the joint. It works in conjunction with the deltoid muscle in helping to do things overhead. For throwing athletes or for anyone who works with overhead lifting, the rotator cuff is critically important. It is also balances the upward pull of the deltoid to some degree. So someone who has a large rotator cuff tear may have difficulty raising their arm up because the humeral head is not stabilized by the rotator cuff, even though their deltoid works perfectly. That is why patients with large tears can only lift their arms up to shoulder level at best.
Shoulder1: How is the rotator cuff damaged or torn?
The most common way for the cuff to be damaged is through either trauma or repetition. I would say of the two, repetition is more common. Over the years someone who paints ceilings for a living may go through that overhead motion of painting over and over again, thousands of cycles for the year. Let’s say a little bone spur on the acromium rubs against the cuff during that time. Eventually, it causes tendonitis, which over time leads to a small rotator cuff tear and that would be secondary to the process of impingement. The other possibility is someone who may or may not have problems with their shoulder, like occasional bursitis or something, may fall and land on the shoulder and then rupture or tear the rotator cuff. Those are probably the most common methods.
Shoulder1: Could you explain briefly how you repair the rotator cuff?
Generally, my approach to repairing the rotator cuff depends on the size and the location of the tear. There are a number of aids to help me to determine that prior to going to the operating room. Perhaps the most useful information can be gleaned from the physical examination and from the results of the MRI. From the physical exam, people who have difficulty with small rotator cuff tears maintain power in the overhead motion and have quite a bit or pain—especially night pain. When they lie down at night, it increases the blood flow to the shoulder and it throbs more, so many patients with small cuff tears are okay during the day but at night they can’t sleep, which eventually brings them into the office.
A loss of external rotations that usually indicates a large cuff tear, and those folks generally have difficulty raising their arms up above shoulder level. The MRI is helpful because it will show the location and the position of the tear and it also gives us an idea about how old the tear is. If the muscle bellies are all atrophied, then we know it is not an acute tear. It is important to know how long the tear has been there, because it helps us to determine how we can fix it.
Shoulder1: You were one of the first to study how consistent, smaller loads—not one large load—may wreck a rotator cuff repair. What led you to break away from the mold in studying this?
The purpose of that study was actually to look at different methods of repairing a cuff tear. When you repair the rotator cuff you can repair it either arthroscopically or you can take an open approach. If you do an open approach, there is the traditional approach where you taken down the deltoid, and then there is the approach where many of us who operate on a lot of shoulders opt for, which is it use what is called a mini-lateral approach, where we do most of the work through the scope. For large tears that cannot be done arthroscopically, we make a little split in the deltoid, basically on the side of the arms, saving that deltoid as much as possible.
When you repair a cuff, you are reattaching the tendon to bone. You use either sutures through the cuff and through the bone, or anchors that go into the bone and then go up to the tendon to hold it down while it is healing. A number of years ago, I started combining those two techniques using sutures through the cuff and through the bone and then a row of anchors right at the edge of the articular surface. The idea behind that is that it increases the bone tendon contact areas and makes for a stronger repair, and if any one of those sutures happens to break, the repair doesn’t necessarily fail. And so the study that one our fellows did with me last year was to look at comparing singular site fixation compared to dual site fixation, and how they faired. The interesting thing about dual site fixation was that under cyclic or repetitive loading, the dual site maintained the bone contact areas better than the single site, which tended to take away from the bone once the load was applied. The dual site fixation was stronger than the single site fixation, but probably the most interesting thing about the study was that it actually maintained the repair thought cyclic loading better and that has ramifications for how you do your post-operative physical therapy.
Shoulder1: You have done a great deal of work studying the anatomy of the shoulder. Has anything in your work surprised you?
I think that one of the interesting things that I have found when we looked at the anatomy of the rotator cuff a few years ago was that the discrepancy from the arthroscopic view and the open view was great. Most arthroscopists have tended to view the area from a particular side of the rotator cuff, and open surgeons tended to look at the other aside. We never really gleaned the fact that there was a relatively wide insertion. So there were always arguments about where do you repair the cuff, at the edge of the articular surface or out on the tuberosity. In fact the cuff insertion was quite broad, and both arthroscopists and open surgeons were right, the cuff stretched from the articular surface out to the tuberosity—I found that very interesting when we did our study.
Shoulder1: You have been involved in a number of different instructional roles. How did you discover this synthesis between orthopedic medicine and teaching?
We put together a CD-ROM, co-sponmsored by New England Baptist Bone and Joint Institute and HealthStream. They wanted to increase the primary care physician awareness in a number of realms of medicine and orthopedics was one of them. They wanted to basically design an orthopedic approach to various parts of the body and so I did the shoulder one. What we did was to give series of lectures to primary care physicians,developed and presented by New England Baptist Hospital, and they were recorded and edited it down so they could have the CD-ROM to refer to later on. It actually worked out quite nicely.
Shoulder1: What kind of things can our readers do to protect their shoulders this summer?
For traumatic injuries from things like skiing or snowboarding—the upper extremity injuries are more common is snowboarding, that is just going to happen, and there is not much that you can do about it. I think it is more important if you are going to be doing a repetitive motion sport like throwing or playing tennis that you spend some time stretching and strengthening your rotator cuff prior to going out and picking up your racket after six or seven months. The best way to do that is just to warm up ahead of time, stretch out your muscles—it just takes ten minutes. If you want to strengthen your rotator cuff, you could do external rotation exercises at your side using stretch elastic material or moving two or three pound weights. Strengthening the lower part of the cuff helps improve the stability of the shoulder and ultimately is beneficial in treating impingement.